Rotary cutoff apparatus

Abstract

This invention relates to a rotary cutoff apparatus, which permits easy speed control without needing high-level skill or technique and also allows ready replacement of its anvil member. The apparatus is provided with a knife cylinder, which has a knife arranged on its outer circumferential surface and is rotatably supported, and an anvil member with which a free edge of the knife can be brought into contact upon rotation of the knife cylinder, whereby a travelling band-shaped sheet is nipped between the knife and the anvil member and is hence cut off. The knife is supported on the knife cylinder via a spring having spring force sufficient to bear cutting force required to cut off the band-shaped sheet so that the knife is displaceable in a loaded direction upon cutting off the band-shaped sheet. The rotary cutoff apparatus according to the present invention can be arranged, for example, in a production line for a band-shaped sheet material such as a corrugated fiberboard sheet.

What is claimed is:  
     
         1 . A rotary cutoff apparatus provided with a knife cylinder, which has a knife arranged on an outer circumferential surface thereof and is supported rotatably, and an anvil member with which a free edge of said knife can be brought into contact upon rotation of said knife cylinder, thereby nipping a travelling band-shaped sheet between said knife of said knife cylinder and said anvil member to cut off said band-shaped sheet, wherein: 
 said knife is supported on said knife cylinder via a cushioning support mechanism having cushioning force sufficient to bear cutting force required to cut off said band-shaped sheet so that said knife is displaceable in a loaded direction upon cutting off said band-shaped sheet.    
     
     
         2 . A rotary cutoff apparatus according to  claim 1 , wherein said anvil member has been subjected to coating treatment at a surface thereof where said free edge of said knife can be brought into contact with said anvil member.  
     
     
         3 . A rotary cutoff apparatus according to  claim 1 , wherein said cushioning support mechanism comprises a spring.  
     
     
         4 . A rotary cutoff apparatus according to claim  1 , wherein said cushioning support mechanism comprises a fluid-filled cushion tube.  
     
     
         5 . A rotary cutoff apparatus according to  claim 2 , wherein said anvil member carries at said surface thereof a coating layer formed by conducting spraying of a hard material as said coating treatment.  
     
     
         6 . A rotary cutoff apparatus according to  claim 5 , wherein said hard material is a carbide cermet.  
     
     
         7 . A rotary cutoff apparatus according to  claim 5 , wherein said hard material is a ceramic.